Background and Importance Patients with hypercholesterolaemia are at risk of cardiovascular events. Some patients have to resort to monoclonal antibody treatments to lower their blood cholesterol levels, despite taking statins at full doses.

Aim and Objectives The aim of this study is to determine the reduction of LDL cholesterol (LDL-c) with PCSK9 inhibitors (alirocumab and evolocumab) in patients with mixed dyslipidaemia, atherosclerotic cardiovascular disease or familial hypercholesterolemia.

Retrospective observational study Adult patients under treatment with ALI or EVO, with at least 12 weeks of follow-up were included. Patients without control laboratory tests after initiation of therapy were excluded.

Primary endpoint of the study was the percentage reduction in LDL-c with respect to baseline.

Retrospective data collection was carried out using electronic medical records (Selene®) and the analysis results software (INFINITY). The Mann-Whitney U test was used to determine whether there were differences in the percentage reduction of LDL-c with respect to baseline between patients treated with alirocumab and evolocumab.

Analyses were performed using SPSS/PC statistical software (version 24.0 for Windows, SPSS, Inc, Chicago, IL).

Results Eighty-eight patients were analysed, of whom 67% were male and the median age 59 ± 9 years.

Of the 88 patients, 61% were diagnosed with mixed dyslipidaemia, 31% with familial hypercholesterolemia, and the remainder with atherosclerotic cardiovascular disease. Eighty-one percent of the patients were treated with alirocumab and the remainder with evolucumab.

The baseline LDL-c level was 156 mg/dL [126–188], total cholesterol 238 mg/dL [202–266], HDL cholesterol 45 mg/dL [37–54] and triglycerides 183 mg/dL [114–250]. At the patients‘ last blood test, after a minimum of 12 weeks from the start of treatment, LDL-c was 60 mg/dl [37–67], total cholesterol 137 mg/dl [114–170] and HDL cholesterol 48 mg/dl [41–60].

The median percent reduction in LDL-c from baseline in patients on PCSK9 inhibitor treatment was 45%. This percent reduction was 43% while in patients on evolocumab treatment it was 46%, U = 552, z = -0.374, p=0.708.

Conclusion and Relevance Treatment with PCSK9 inhibitors reduces basal LDL-c by 45%. No statistically significant differences were found according to the treatment used (alirocumab or evolocumab), p=0.708. .

Conflict of Interest No conflict of interest.